H1B Dropbox Mumbai -> Chennai

Hello, my dropbox appointment is scheduled on January 10th, 2024. Chennai VAC.

1. I'll submit the necessary documents in Mumbai and pay Rs. 850 for them to be sent to Chennai, correct?

2. Do I need to submit Employer verification letter as well? Or just passport, photos as per US standard, I-797 copy?

3. I have chosen the pickup option, so I will pick up the documents from the Mumbai office, correct? Do I need to pay any additional fees?